Senior Backend Engineer, Key Management

About the team

The KMS team sits at the very heart of Fireblocks’ platform and is a pivotal team in the company.

The team is responsible for the cryptographic backbone of the platform that secures customers’ most sensitive secrets. Every transaction signing flow. Every cosigner interaction. Every key generation ceremony. Every backup and recovery mechanism. If it touches a private key - it touches this team.

The team performs mission-critical engineering at high scale, working on systems where failure is not an option, security is existential, performance matters and correctness is everything. The work is deep, challenging, and intellectually demanding - blending modern C++ systems programming with distributed backend architecture and applied cryptography.

If you enjoy solving problems where security, scale, distributed systems, and adversarial thinking collide - this is your kind of challenge.

What You'll Do:

You’ll collaborate with backend engineers, infrastructure teams and security and cryptography researchers to ship production-grade highly secure digital signing systems, balancing cryptographic rigor, performance constraints, and distributed reliability in a domain where small mistakes have massive consequences. This includes:

• Architecting, designing and implementing distributed backend services responsible for key generation, storage and lifecycle management
• Developing high-assurance signing protocols and signing flows (utilizing MPC or external signing devices)
• Building secure backup and disaster recovery mechanisms for cryptographic material
• Hardening systems against adversarial conditions and real-world attack vectors
• Optimizing performance-critical components that execute complex operations

What You'll Bring:

• 7+ years of strong backend experience in production systems
• Experience building large-scale backend or distributed systems (SaaS experience strongly preferred)
• Experience working with distributed SQL DBs
• Experience working with cloud and backend technologies (e.g. Docker, K8S, AWS, Azure, DataDog, Prometheus)
• Deep understanding of concurrency, memory management, system design, and performance optimization
• Experience working on mission-critical or high-reliability platforms
• A strong security engineering mindset

Strong Advantage

• Experience with TypeScript 
•  Experience with multiple development environments, languages and paradigms
• Experience with cryptography, MPC, threshold signatures, or key management systems
• Familiarity with blockchain technologies
• Experience with confidential computing technologies
• Experience integrating with HSMs or secure enclaves
• Background in highly security-sensitive environments